The present invention relates to a valve for controlling fluids, in particular a fuel injection valve, with an integrated device for determining pressures, and to a method for determining pressures and pressure changes in a combustion chamber of a motor vehicle.
In conventional engines, so-called knocking sensors are used to determine knocking, for instance. These known knocking sensors detect engine knocking by excitation of a seismic mass. The mechanical pulses are converted into electrical signals, which are evaluated by a control unit. Knocking sensors are connected from outside mechanically solidly to the cylinder or engine block. With such knocking sensors, however, only knocking can be detected. Combustion chamber pressure sensors are also known, which are provided in their own bore in the cylinder head for continuous measurement of the gas pressure in the combustion chamber. A disadvantage of these known pressure pickups is that each must be provided with its own bore in each cylinder in the cylinder head of the engine and also each with its own line per cylinder, which is relatively complicated and makes the production costs higher.
What is known as ion current measurement is also known, which is based on measuring the current flow via ions when an electrode voltage is applied, the ions being produced upon ignition of the mixture by an ignition spark. If as a result of the measuring voltage applied to the spark plug electrodes current flows via these ions, then the gas mixture is ignited. By means of ion current measurement, for instance at the spark plug electrodes, it becomes possible to obtain controlled variables for controlling the engine. By means of ion current measurement, misfiring and engine knocking can for instance be detected, and mixture preparation can be optimized.
The known devices for detecting misfiring or knocking are relatively complicated, however, and entail additional cost because of additional components and their assembly.